sign in sign up
<<
Home , Ovarian torsion, Pelvic pain

Acute Pelvic Danielle DeMulder1, Joanna Riess2, Sandra J. Allison2

Acute in a woman can be due to gynecologic, [4], because the ipsilateral usually twists with gastrointestinal, and urinary tract disorders. This chapter fo- the [5]. Adnexal torsion can, however, occur with isolat- cuses on gynecologic causes of acute pelvic pain. Pregnan- ed torsion of the ovary and even more rarely involve only the cy-related disorders, such as ectopic , spontaneous fallopian tube [4]. Given the rarity of isolated fallopian tube abortion, and ovarian hyperstimulation, are not covered, nor torsion (an incidence of 1 in 1.5 million women), this diagnosis are postpartum and postsurgical causes. is rarely made preoperatively [6]. occurs when the vascular pedicle of the Acute pelvic pain, defined as the sudden onset of lower ovary twists along its suspensory ligament and causes initial abdominal or pelvic pain lasting less than 3 months [1], is a obstruction of venous and lymphatic outflow and eventual ar- common urgent clinical presentation. Women frequently present terial compromise with resultant ischemia and hemorrhagic to the emergency department after hours. More than one third infarction [7]. Ovarian torsion can occur at any age but most of women of reproductive age experience nonmenstrual pelvic frequently occurs in women of reproductive age [4]. The char- pain [2]. Acute pelvic pain can pose a diagnostic challenge be- acteristic clinical presentation of ovarian torsion is acute onset cause the clinical history, symptoms, and physical examination of sharp, intermittent pain localized to a lower quadrant, of- findings are often nonspecific, and the clinical presentations ten with associated and [8]. A tender adnexal of the underlying gynecologic, obstetric, urologic, and gas- mass may also be palpated at physical examination [8–10]. In trointestinal conditions often vary widely and can frequently 50–81% of cases of ovarian torsion, an underlying lesion is overlap. Although some of the common conditions, such as seen in the ipsilateral ovary [8, 9, 11, 12]. ruptured or hemorrhagic ovarian cysts, are self-limiting, it is The most consistent gray-scale sonographic finding in ovar- imperative that urgent conditions that may necessitate inter- ian torsion is unilateral ovarian enlargement [5, 13–15] with vention or surgery, such as ovarian torsion, pelvic inflamma- variability in the internal ovarian architecture (Fig. 1). In a pre- tory disease (PID), and , be considered when a menopausal woman, the ovary is considered enlarged if the premenopausal woman has acute pelvic pain. greatest ovarian dimension is more than 4 cm [7, 15] or the The American College of Radiology Appropriateness Cri- volume is larger than 20 cm3 [7]. An underlying cystic, solid, teria list pelvic sonography as the preferred first-line imaging or mixed solid and cystic mass may be seen within the affected modality in the evaluation of acute pelvic pain in pregnant ovary [8, 9, 12, 15–17], or the enlarged ovary may have a het- women and nonpregnant women of reproductive age when erogeneous internal echotexture, reflecting intraovarian edema an obstetric or gynecologic condition is suspected and in the and hemorrhage. Multiple small, uniform, peripherally located initial assessment of a suspected nongynecologic condition cysts displaced to the cortex of the engorged ovary are seen in in a pregnant patient [3]. This can be attributed to its ready as many as 74% of cases [5, 13, 15]. This finding is sometimes availability, cost-effectiveness, noninvasive nature, and lack of referred to as the string-of-pearls sign [15]. Free fluid may be ionizing radiation. Sonography can also prove helpful in the present owing to transudation from the torsed ovary secondary assessment of suspected gastrointestinal or urinary tract abnor- to venolymphatic obstruction [13, 16]. In ovarian torsion, the malities in a nonpregnant woman; however, CT is typically the affected ovary can be found in an unusual location (Fig. 1), preferred first-line imaging modality for those patients [3]. such as in the midline or cranial to the uterine fundus [15, 18]. Transducer palpation over the affected ovary may elicit local Adnexal Torsion tenderness at transvaginal sonography [15]. The term adnexal torsion broadly refers to torsion of the A specific finding of ovarian torsion that may be seen with ovary, fallopian tube, or both. It most commonly involves both gray-scale ultrasound imaging with or without color Doppler

1Department of Radiology, MedStar Georgetown University Hospital, Washington, DC.

2Washington Radiology Associates, PC, 3015 Williams Dr, Ste 200, Fairfax, VA 22031. Address correspondence to S. J. Allison ([email protected]).

186 The Dark Side of Radiology: Multispecialty After-Hours Imaging Acute Pelvic Pain technique is the swirling appearance of with surgically confirmed ovarian torsion ings include a mass in the adnexa, which the vessels within the twisted vascular (Fig. 1). In a study in which color Dop- is sometimes located in the midline, en- pedicle (Fig. 1), sometimes called the pler findings were abnormal in 93% of pa- gorged vessels on the affected side, uter- whirlpool sign [7, 19]. This sign has the tients, the most common (40%) abnormal ine deviation toward the side of the tor- appearance of a round hyperechoic struc- flow pattern was complete absence of both sion, and fallopian tube thickening [7, 15, ture with a target appearance character- arterial and venous flow [16]. In order of 22]. Associated findings of subacute ovar- ized by several concentric hypoechoic decreasing frequency, the other flow pat- ian hematoma and abnormal or absent bands. The twisted vascular pedicle was terns were decreased venous and absent ovarian enhancement are better delineated found to have sensitivity of 88% and arterial flow (33%), decreased venous and with CT or MRI than with ultrasound [7]. specificity of 87% (93% positive and arterial flow (13%), decreased arterial and 76% negative predictive values) in one absent venous flow (7%), and normal ar- Pelvic Inflammatory Disease study [9] but was seen in only 13% of terial and venous flow (7%). The ovary PID is a frequent cause of acute pel- cases in another series [16]. Although it can even appear hyperemic in instances of vic pain, affecting as many as 1.5 mil- may be technically challenging to iden- intermittent torsion-detorsion [21]. Given lion women per year in the United States tify, when seen in conjunction with ovar- the wide range of technical settings, com- [5, 23]. PID is an ascending sexually ian enlargement, the finding of a twisted parison images of the color Doppler ap- transmitted from the to vascular pedicle is considered diagnostic pearance of both is helpful in eval- the upper genital tract with subsequent of ovarian torsion [7]. uations for asymmetric vascularity. infection that can involve the endo- Color Doppler findings can be highly Although ultrasound is the preferred metrium, fallopian tubes, ovaries, and variable and are related to the degree and imaging modality for ovarian torsion, peritoneum. It is most frequently caused chronicity of vascular compromise [7]. CT and MRI can also be helpful in as- by Chlamydia trachomatis or Neisseria Lack of arterial and venous Doppler flow sessment. Like sonography, CT and MRI gonorrhoeae [24]. Encompassed under is helpful as a supporting finding, but the can also reveal an enlarged ovary with or the umbrella term of PID are tuboovar- presence of detectable arterial and venous without an associated underlying ovar- ian abscesses, , , flow does not exclude ovarian torsion [7]. ian mass, peripherally located follicles, and peritonitis. Chronic pelvic pain, In one series [20] Doppler sonographic the twisted vascular pedicle, and from scarring, and increased findings were normal in 60% of patients [7, 15, 22] (Fig. 2). Additional CT find- risk of may result

A B C

Fig. 1—29-year-old woman in emergency department with acute left-sided pelvic pain. A, Transvaginal long-axis ultrasound image of left ovary shows enlargement of ovary (asterisk) with follicles displaced to periphery. B, Long-axis transvaginal image of shows relative location of ovary in cul-de-sac. C, Transvaginal longitudinal ultrasound scan through left adnexa shows round hyperechoic structure with swirling appearance compatible with twisted vascular pedicle (arrow). D, Color and spectral Doppler images of left ovary show presence of arterial flow. This finding does not exclude diagnosis of ovarian torsion, which was found at surgery. D

The Dark Side of Radiology: Multispecialty After-Hours Imaging 187 DeMulder et al.

[25]. Known risk factors for PID include young age (15–24 years), numerous sex- ual partners, history of sexually trans- mitted , , and history of surgical instrumentation via the cervix [26]. The clinical presentation of PID is variable, the most common symptom being lower . Patients may also report fever, malaise, , , dysuria, or ; PID may even be asymp- tomatic [27]. Physical examination may A B reveal abdominal tenderness, cervical Fig. 2—32-year-old woman with acute right lower quadrant pain and torsed right ovary. A, Coronal reconstructed contrast-enhanced CT image shows swirl of vessels (arrow) in right motion, and adnexal tenderness. The pelvic region. patient may also have a fever, leukocy- B, Coronal contrast-enhanced CT image shows enlarged right ovary (arrowheads) with relatively less tosis, elevated erythrocyte sedimenta- enhancement than normal-sized left ovary (arrow). tion rate, positive result of endocervical Gram stain, positive results of culture for C. trachomatis or N. gonorrhoeae, puru- lent cervical exudate on culdocentesis or , or the finding of pelvic abscess during bimanual examination or pelvic ultrasound examination [28]. Early in the course of PID, ultrasound findings may be normal. As the infection progresses, some of the reported early sonographic features of PID include in- A B creased echogenicity and prominence of Fig. 3—22-year-old woman with pelvic pain due to pelvic inflammatory disease. peritoneal fat in the , loss of nor- A, Longitudinal transvaginal ultrasound image shows thick-walled tubular structure in right adnexa mal tissue planes, ill definition of uterine distended with echogenic material. serosal contours, increased uterine size, B, Longitudinal transvaginal ultrasound image shows fluid-debris levels arrows( ) in distended left fallopian tube. and endometrial thickening or fluid [5, 13, 15]. Nonspecific free pelvic fluid, [29] (Fig. 3). When viewed in cross-sec- lopian tube have broken down such that which may be echogenic, is commonly tion, redundant folding of the fallopian separate structures can no longer be de- seen in PID [27]. tube on itself results in an appearance of lineated, the condition is referred to as a Normal fallopian tubes are not typi- incomplete septa, which in addition to tuboovarian abscess [13] (Fig. 4). Without cally visualized during routine pelvic thickened endosalpingeal folds accounts intervention, a tuboovarian abscess may sonography, but in patients with salpin- for the cog wheel sign [13, 29]. Power rupture and cause peritonitis or multiple gitis, swelling of the fallopian tube re- or color Doppler examination of the fal- intraabdominal abscesses. sults in thickening of the tubal wall and lopian tube may show hyperemia of the Although ultrasound is the preferred endosalpingeal folds [29]. Given the ab- fallopian tube walls or endosalpingeal imaging modality for patients with PID, sence of intraluminal pus in salpingitis, folds [13, 29]. CT may have been ordered if a nongyne- the endosalpingeal folds are difficult to In more advanced cases of PID, exuda- cologic cause of abdominal pain was ini- delineate. The ultrasound appearance is tion of pus from the fallopian tube into the tially suspected. CT can also be a useful an ill-defined, elongated, solid-appear- peritoneum leads to involvement of the supplement for delineating the extent of ing mass adjacent to, but separate from, ovary, initially causing ovarian enlarge- disease, evaluating for associated com- the ovary. If there is distal luminal oc- ment, with indistinct ovarian borders [5], plications, and follow-up in cases refrac- clusion of the fallopian tube, pyosalpinx sometimes with numerous small cysts tory to antibiotic therapy. CT findings will result and be seen as a tubal struc- [13]. In later stages, an inflammatory mass are usually normal in uncomplicated ture with purulent echogenic material involving the fallopian tubes and adjacent acute salpingitis; however, some cases [13, 29] (Fig. 3). Fluid-debris levels are ovary may develop. When a separate ova- reveal nonspecific fluid in the cul-de-sac often visualized within the dilated fal- ry can still be identified, the condition is [30]. With progression to pyosalpinx, lopian tube with the less frequent find- referred to as tuboovarian complex. Once serpiginous tubular structures represent- ing of intraluminal gas or air-fluid levels the architecture of the ovary and the fal- ing a fallopian tube distended with pus

188 The Dark Side of Radiology: Multispecialty After-Hours Imaging Acute Pelvic Pain are seen. Tuboovarian abscess appears as unilateral or bilateral hypodense adnexal masses with thick, enhancing walls and thick septations [30] (Fig. 4). Associ- ated CT findings in PID include utero- sacral ligament thickening, thickening and anterior displacement of the broad ligament, edema of the parapelvic and presacral fat with resultant hyperattenua- tion and fat stranding, ill definition of the uterus and nearby bowel wall, inflamma- A B tory paraaortic lymphadenopathy, and Fig. 4—33-year-old woman with pelvic pain and cervical motion tenderness. A, Transvaginal sonogram of right adnexa shows complex cystic mass. Ovary cannot be separated hydronephrosis [30, 31]. Internal gas from cystic , compatible with tuboovarian abscess. bubbles are an infrequent finding in tu- B, Axial contrast-enhanced CT image shows complex mass with thick, enhancing walls and boovarian abscesses [31]. septations. Hyperattenuation of ill-defined uterus asterisk( ) is evident.

Functional Ovarian Cysts Comprehension of the natural evolu- Failure to regress of an incompletely tion of the sonographic appearance of developed follicle may result in a fol- blood is helpful in the evaluation of both licular cyst. Likewise, the hemoperitoneum and hemorrhagic ovar- may not resorb after ovulation. Enlarge- ian cysts. Fresh blood is characteristical- ment of either due to accumulation of ly anechoic and turns hyperechoic when fluid, rupture, internal hemorrhage, or clot forms in the subacute stages (Fig. 6). resultant torsion can cause acute pain Over time, as the RBCs hemolyze, the and is among the most common reasons echogenicity of blood progressively de- that afebrile nonpregnant women of re- creases in proportion to the hematocrit, productive age present to the emergency and the blood may be entirely anechoic department with acute pelvic pain [5]. after 96 hours [33]. Hyperechoic acute The hemorrhagic cysts in premeno- blood clot may be differentiated from pausal women are typically hemorrhagic nearby bowel by its avascularity, non- Fig. 5—22-year-old woman with acute right corpora lutea. The clinical presentation tubular shape, and absence of peristalsis pelvic pain. Coronal transvaginal sonogram is acute onset of severe but self-limited during real-time imaging [24]. of right ovary shows thick-walled cyst. Wall is relatively hypoechoic. Few echoes within cyst pain localized to one side of the pelvis As they evolve, hemorrhagic ovar- represent hemorrhage. Color Doppler imaging [24]. The WBC count should be normal ian cysts display a wide spectrum of shows peripheral vascularity typical of [24, 32], and correlation should be made sonographic appearances depending on corpus luteum. with the patient’s menstrual cycle, be- when they are imaged as the cyst pro- cause temporal relation of a symptom- gresses through stages of acute hemor- continued evolution, coalescence of the atic cyst to the appropriate phase of the rhage, formation and retraction of clot, thrombus occurs within the cyst, and menstrual cycle is supportive. and eventual resolution [34]. Typically, retractile clot develops, which must be Functional follicular cysts are thin- a hemorrhagic cyst appears as a complex avascular and often forms angular mar- walled and contain anechoic fluid. Cor- cystic mass containing internal echoes. gins (Fig. 6). This retractile clot is often pora lutea have thick hypoechoic walls, For this reason, posterior through-trans- dependent within the cyst but at times is sometimes with internal crenulation, or mission and absence of internal vascu- adherent to the cyst wall [24]. Doppler may appear solid. Peripheral vascularity larity should be confirmed to establish ultrasound is not infallible in showing is present during color Doppler imaging the basic cystic nature of the mass [34]. tumor vascularity. If features cause con- (Fig. 5). When an ruptures, In the acute phase, a hemorrhagic cyst cern about a focal tumor nodule within the involved ovary may have a normal has a thin wall with an internal pattern of a cystic structure (such as adherence sonographic appearance if the rupture diffuse low-level echoes [24]. With sub- to the wall, rounded shape, poor poste- is complete. The ruptured fluid may re- sequent lysis of RBCs and the formation rior through-transmission secondary to sorb or diffuse throughout the peritoneal of strands of fibrin, the hemorrhagic cyst dense internal architecture), follow-up cavity [24]. An ovarian cyst that has not develops an internal architecture, which ultrasound should be performed in 6–8 completely ruptured may have a cre- has been described as a lacelike or fish- weeks to document expected evolution nate appearance, with internal low-level net reticular pattern of internal echoes or resolution of the hemorrhagic cyst and echoes or blood clot [24]. There may or [24] with avascular linear strands that exclude a tumor nodule within a cystic may not be adjacent free fluid. should be smooth and thin (Fig. 6). With ovarian neoplasm [24, 34].

The Dark Side of Radiology: Multispecialty After-Hours Imaging 189 DeMulder et al.

A B C Fig. 6—Evolution of hemorrhagic cysts. A, Ultrasound image shows hyperechoic clot within subacute hemorrhagic cyst (calipers). B, Ultrasound image shows fine linear echoes with lysis of RBCs and formation of fibrin strands. C, Ultrasound image shows retractile clot (asterisk) with characteristic angular margins.

When hemoperitoneum is present graphic evaluation. Many cases of endo- superior to ultrasound in the diagnosis and the ovaries appear normal, CT can metrioma involve microscopic ovarian of (specificity as high as be a useful adjunct for excluding other implants, too small to be detected with 98%) owing to its ability to depict old intraabdominal processes, such as a rup- imaging [30]. In a study by Mais et al. blood products [41]. On MR images en- tured hepatic adenoma, which can cause [38], transvaginal ultrasound was found dometriomas have increased T1-weight- hemoperitoneum in a young woman [30]. to have a sensitivity of 88% and specific- ed signal intensity from blood products The CT attenuation within a hemorrhagic ity of 90% for differentiating endometrio- and often have low T2-weighted signal cyst and of the hemoperitoneum will be ma from other ovarian lesions [38]. intensity, the so-called shading sign, increased, typically to 25–100 HU [19]. can be solitary or which is unique to endometrioma. multiple and are present in both ova- ries in as many as 50% of cases. They Nongynecologic Disorders Endometriosis is characterized by appear as hypovascular cystic lesions In the setting of acute pelvic pain, es- ectopic endometrial tissue, primarily most often with homogeneous low-level pecially when findings of evaluation of within the ovaries and pelvic peritoneum echogenicity (Fig. 7). Other character- the uterus and ovaries are normal, non- [35]. As much as 80% of endometriosis istics, such as internal fluid-fluid levels, gynecologic causes should be considered. occurs within the ovaries [19]. Endome- peripheral nodules, and echogenic foci, Many of the nongynecologic causes of triosis affects approximately 10% of pre- can also be seen [39] (Fig. 7). Endome- pelvic pain are amenable to sonographic menopausal women [19]. The pathogen- trioma rupture results in the formation evaluation. These include distal uretero- esis of endometriosis is a controversial of fibrous adhesions, which can have lithiasis and appendicitis. Distal ureteral subject with multiple proposed theories the appearance of a complex mass. This stones are identified as shadowing echo- and has yet to be fully elucidated. The appearance can mimic tuboovarian com- genic foci within the ureter. Laing et al. most widely accepted theory involves plex or abscess, hemorrhagic cysts, and [42] found that compared with a trans- ectopic implantation of endometrial tis- ovarian malignancy [40]. abdominal approach, transvaginal ultra- sue by retrograde [36]. Although not feasible in the emer- sound is the optimal modality for the di- Other theories include hematologic or gency setting, MRI is believed to be agnosis of distal ureteral stones. This may lymphatic dissemination. Ectopic endo- metrial tissue is hormone sensitive and can cause cyclic bleeding, pain, and in- fertility [37]. Although most of the pain is chronic, endometriomas can cause acute on , which also can occur in association with secondary in- fection or rupture [19]. Although the definitive diagnosis of endometriosis is made with surgical and histologic evaluation, imaging can play A B an important role in the care of patients Fig. 7—28-year-old woman with acute pelvic pain and history of endometriosis. with suggestive clinical signs and symp- A, Coronal transvaginal sonogram of uterus shows bilateral cystic ovarian lesions with internal homogeneous echoes (calipers, asterisks). toms. Ovarian endometrial implants must B, Coronal transvaginal sonogram of left ovary shows multiple cysts in ovary. Largest cyst (asterisk) be large enough to be detected at sono- contains peripheral echogenic foci typical of endometriomas.

190 The Dark Side of Radiology: Multispecialty After-Hours Imaging Acute Pelvic Pain

torsion. Fertil Steril 2000; 73:1047–1050 21. Middleton WD, Kurtz AB, Hertzberg BS. Ultrasound: the requisites, 2nd ed. St. Louis, MO: Mosby, 2004 22. Rha SE, Byun JY, Seung EJ, et al. CT and MR features of adnexal torsion. RadioGraphics 2002; 22:283– 294 23. Rein DB, Kassler WJ, Irwin KL, Rabiee L. Direct medical cost of pelvic inflammatory disease and its sequelae: decreasing, but still substantial. Obstet Gynecol 2000; 95:397–402 24. Cicchiello LA, Hamper UM, Scoutt LM. Ultrasound evaluation of gynecologic causes of pelvic pain. Ultrasound Clin 2010; 5:209–231 25. Goyal M, Hersh A, Luan X, Localio R, Trent M, Za- outis T. National trends in pelvic inflammatory dis- ease among adolescents in the emergency depart- A B ment. J Adolesc Health 2013; 53:249–252 26. Khan ZE, Rizvi JH. Pelvic inflammatory disease and Fig. 8—24-year-old woman with acute right pelvic pain. pelvic abscesses. Rev Gynaecol Perinatal Pract 2006; A, Transvaginal sonogram in region of tenderness shows blind-ending tubular structure (arrows) 6:185–191 compatible with distended appendix. 27. Schmitz G, Tibbles C. Genitourinary emergencies B, Color Doppler image shows increased vascularity. Acute appendicitis was found at surgery. in the nonpregnant woman. Emerg Med Clin North Am 2011; 29:621– 635 be due to the higher-frequency transducer 5. Kaakaji Y, Nghiem HV, Nodell C, Winter TC. Sono- 28. Hager WD, Eschenbach DA, Spence MR, Sweet RL. used, the endovaginal approach, and the graphy of obstetric and gynecologic emergen- Criteria for diagnosis and grading of salpingitis. cies. Part 2. Gynecologic emergencies. AJR 2000; Obstet Gynecol 1983; 61:113–114 absence of variability in urinary bladder 174:651–656 29. Horrow MM, Rodgers SK, Naqvi S. Ultrasound of distention that is often unavoidable with a 6. Raziel A, Mordechai E, Friedler S, Schachter M, Pan- pelvic inflammatory disease.Ultrasound Clin 2007; transabdominal approach. skey M, Ron-El R. Isolated recurrent torsion of the 2:297–309 fallopian tube. Hum Reprod 1999; 14:3000–3001 30. Bennett GL, Slywotzky CM, Viovanniello G. Gyne- Transabdominal ultrasound has a re- 7. Duigenan S, Oliva E, Lee SI. Ovarian torsion: diag- cologic causes of acute pelvic pain: spectrum of CT ported sensitivity of 80–94% in the di- nostic features on CT and MRI with pathologic cor- findings. RadioGraphics 2002; 22:785–801 agnosis of acute appendicitis [43]. The relation. AJR 2012; 198:[web]W122–W131 31. Wilbur AC, Aizenstein RI, Napp TE. CT findings in 8. Warner MA, Fleischer AC, Edell SL, et al. Uterine tuboovarian abscess: pictorial essay. AJR 1992; findings consist of a dilated, noncom- adnexal torsion: sonographic findings. Radiology 158:575–579 pressible, tubular, blind-ending appendix 1985; 154:773–775 32. McWilliams GD, Hill MJ, Dietrich CS. Gynecologic (Fig. 8). Pelvic appendicitis, which in- 9. Lee EJ, Kwon HC, Joo HJ, Suh JH, Fleischer AC. Diag- emergencies. Surg Clin North Am 2008; 88:265–283 nosis of ovarian torsion with color Doppler sono- 33. Coelho JC, Sigel B, Ryva JC, Machi J, Renigers SA. B- volves an appendix that extends toward graphy: depiction of twisted vascular pedicle. J mode sonography of blood clots. J Clin Ultrasound the pouch of Douglas, is most optimally Ultrasound Med 1998; 17:83–89 1982; 10:323–327 detected and diagnosed by use of trans- 10. Bayer AI, Wiskind AK. Adnexal torsion: can the ad- 34. Jain KA. Sonographic spectrum of hemorrhagic nexa be saved? Am J Obstet Gynecol 1994; 171:1506– ovarian cysts. J Ultrasound Med 2002; 21:879–886 vaginal sonographic evaluation [44]. 1510 35. Bulun SE. Endometriosis. N Engl J Med 2009; 11. Hibbard LT. Adnexal torsion. Am J Obstet Gynecol 360:268–279 Conclusion 1985; 152:456–461 36. Sampson JA. Peritoneal endometriosis due to 12. Helvie MA, Silver TM. Ovarian torsion: sonographic menstrual dissemination of endometrial tissue One of the most common clinical evaluation. J Clin Ultrasound 1989; 17:327–332 into the peritoneal cavity. Am J Obstet Gynecol 1927; problems in women presenting to the 13. Andreotti RF, Harvey SM. Sonographic evalua- 14:422–269 emergency department is acute pelvic tion of acute pelvic pain. J Ultrasound Med 2012; 37. Giudice LC, Kao LC. Endometriosis. Lancet 2004; 31:1713–1718 364:1789–1799 pain. Imaging is essential in the evalu- 14. Graif M, Shalev J, Strauss S, Engelberg S, Mashiach 38. Mais V, Guerriero S, Ajossa S, Angiolucci M, Paoletti ation of these patients, and ultrasound is S, Itzchak Y. Torsion of the ovary: sonographic fea- AM, Melis GB. The efficiency of transvaginal ultra- the primary initial modality. Thorough tures. AJR 1984; 143:1331–1334 sonography in the diagnosis of endometrioma. 15. Chang HC, Bhatt S, Dogra VS. Pearls and pitfalls in Fertil Steril 1993; 60:776–780 knowledge of the sonographic features diagnosis of ovarian torsion. RadioGraphics 2008; 39. Chamié LP, Blasbalg R, Pereira RM, Warmbrand G, of the most common causes of pain, in- 28:1355–1368 Serafini PC. Findings of pelvic endometriosis at cluding ovarian torsion and PID, may 16. Albayram F, Hamper UM. Ovarian and adnexal tor- transvaginal US, MR imaging, and laparoscopy. Ra- sion: spectrum of sonographic findings with path- dioGraphics 2011; 31:E77–E100 obviate additional imaging and result in ologic correlation. J Ultrasound Med 2001; 20:1083– 40. Friedman H, Vogelzang RL, Mendelson EB, Neiman prompt diagnosis and treatment. 1089 HL, Cohen M. Endometriosis detection by US with 17. Stark JE, Siegel MJ. Ovarian torsion in prepubertal laparoscopic correlation. Radiology 1985; 157:217–220 REFERENCES and pubertal girls: sonographic findings. AJR 1994; 41. Togashi K, Nishimura K, Kimura I, et al. Endometrial 1. Kruszka PS, Kruszka SJ. Evaluation of acute pelvic 163:1479–1482 cysts: diagnosis with MR imaging. Radiology 1991; pain in women. Am Fam Physician 2010; 82:141–147 18. Mashiach R, Melamed N, Gilad N, Ben-Shitrit G, 180:73–78 2. Hart D, Lipsky A. Acute pelvic pain in women. In: Meizner I. Sonographic diagnosis of ovarian tor- 42. Laing FC, Benson CB, DiSalvo DN, Brown DL, Frates Marx JA, ed. Rosen’s emergency medicine, 8th ed. sion: accuracy and predictive factors. J Ultrasound MC, Loughlin KR. Distal ureteral calculi: detection Philadelphia, PA: Saunders, 2014:266–272 Med 2011; 30:1205–1210 with vaginal US. Radiology 1994; 192:545–548 3. Andreotti RF, Lee SI, Dejesus Allison SO, et al. ACR 19. Potter AW, Chandrasekhar CA. US and CT evalu- 43. Jeffrey RB Jr, Laing FC, Townsend RR. Acute appen- Appropriateness Criteria: acute pelvic pain in ation of acute pelvic pain of gynecologic origin dicitis: sonographic criteria based on 250 cases. Ra- the reproductive age group. Ultrasound Q 2011; in nonpregnant premenopausal patients. Radio- diology 1988; 167:327–329 27:205–210 Graphics 2008; 28:1645–1659 44. Damani N, Wilson S. Nongynecologic applications 4. Sasaki KJ, Miller CE. Adnexal torsion: review of the 20. Peña JE, Ufberg D, Cooney N, Denis AL.. Usefulness of transvaginal US. RadioGraphics 1999; 19:S179– literature. J Minim Invasive Gynecol 2014; 21:196–202 of Doppler sonography in the diagnosis of ovarian S200

The Dark Side of Radiology: Multispecialty After-Hours Imaging 191